Only sort a DataGrid if the column's sortable is set True

Review Request #10168 — Created Sept. 22, 2018 and submitted — Latest diff uploaded




Previously, all arguments to self.request.GET.get('sort', ...) were
passed to self.sort_list even if they were invalid. This could cause
issues where columns collided with methods, such as when giving
?sort=fullname to /users/ which resulted in an Error 500.

Now, in load_state(), a set of sort keys are computed based on what
columns are set sortable, and the column's db_field is only added to
self.sort_list if the corresponding column is in this set.

Two unit tests have been added to exercise this functionality in
ascending and descending order, passing in an invalid sort key and
checking that self.sort_list is empty.

Two additional unit tests sort on one valid and one invalid key in
ascending and descending order and check that self.sort_list only
contains the valid key. All four of these unit tests pass.

All tests in djblets.datagrid.tests and
reviewboard.datagrids.tests passed without problems.